Ecchi is a Japanese term meaning sexy or erotic, anything that evolves sexy characters. Derived from the word "Hentai" but their meanings are completely different. Ecchi walks that line between sexy, but never crosses it into full graphic nudity or sex.

This is the act of secretly watching a person or group to gather information, often for political purposes. Spies typically disguise themselves so that they might sneak around. Espionage is also frequently tied to assassination plots.

Used frequently in Anime to either recap past events or provide a back story for a character, either their origin story or their off-screen training of new attack. Sometime and entire episode/chapter would be a entire flashback.

Humans are typically depicted as the dominant species of the planet Earth, and sometimes of other planets. Humans often mirror their real life counterparts in terms of abilities and intellect, while other times they can achieve superhuman feats.

Characters who exercise their strong libidinous desires in unwholesome ways, such as peeping on the objects of their desire, making inappropriate comments, stealing underwear etc.
Though typically middle-aged or elderly men with a penchant for young girls, there are probably a few dirty old women out there.

In Japanese, otaku means people who are obsessed over something. Usually, it is in reference to anime, manga, and video games. In the western world, the word is frequently designated to a fan of anime, manga, video games and/or Japanese culture.

In anime and manga, girls sometimes admire each other's assets, to the point of groping either with or without permission. This concept applies to any part of the body and either gender, but it's usually all about boobs.

"Tricky" refers to content that sexualizes minors or characters with the appearance of minors. Generally, these characters have a physical appearance that puts them noticeably under the legal age of consent in the United States.

Those moments when clothing slips or falls off by accident, revealing a little too much. Usually played of for comedic purposes.
Wardrobe Malfunction should not be confused with "Clothing Damage" which is usually the after effect of fights.